Conventional turbo compressors known in the art are designed to compress a gas. They are normally composed of many stages (rotating impellers and static diffusers) stacked on a flexible shaft rotating at relative high speed. Critical mechanical elements such as bearings and thrust balancing devices are often exposed to the process fluid.
Any impurities in the process fluid such as solids or liquid are detrimental to both the thermodynamic and mechanical performance. When impurities or liquid are expected to be present in the process stream different types of auxiliary equipment are utilized to clean or dry the process gas upstream the compressor. Typically a gas scrubber and/or heat exchangers may be used to remove liquid from the process fluid.
Known attempts to modify conventional turbo compressors to be so called “liquid tolerant” have had very limited success and only very low liquid fractions can be accepted in some rear cases. However, even in these cases the presence of liquid will cause deterioration in the thermodynamic and mechanical performance.
The challenges are even greater when designing a gas compressor for use in a subsea environment. In particular, the robustness of the design and physical dimensions of the compressor should be considered when the compressor is to be deployed in subsea environments with challenging weather conditions. For example in the arctic, where there are significant oil- and gas resources, subsea deployment techniques such as via a ship's moon pool are of great benefit due to the presence of moving ice.